Improve PApplet draw method's documentation or behavior

Created by: agreyson

Description

A subclass of PApplet that overrides draw and invokes super.draw (which could happen inadvertently if using an IDE such as IntelliJ that auto-completes overridden methods) will not respond to user events (e.g. mouse clicks). Currently, this is a tricky bug to fix unless a developer is savvy enough to hunt down this GitHub repository and read the implementation of the PApplet draw method. There is a print statement in the implementation that might provide a clue, but it's currently commented out. Uncommenting and providing more details in that print statement would be helpful. For example, you could advise the developer to reconsider invoking super.draw, and explain that it will suspend event handling. (That said, perhaps a better solution would be for the PApplet draw method not to assume that it's being invoked because the subclass has not overridden draw.)

Expected Behavior

public void draw() {
// if no draw method, then shut things down
System.out.println("You're either not overriding the draw method or invoking super.draw from your draw method.");
System.out.println("If the latter, are you sure you mean to do this? Invoking super.draw will suspend event handling.");
finished = true;
}

Current Behavior

public void draw() {
// if no draw method, then shut things down
//System.out.println("no draw method, goodbye");
finished = true;
}

Steps to Reproduce

1. Subclass PApplet.
2. Override the draw method in the subclass.
3. Invoke super.draw from the new draw method.

Your Environment

• Processing version: 4.1.1
• Operating System and OS version: macOS Ventura 13.1
• Other information: I'm using IntelliJ, not the Processing application, and I'm subclassing PApplet and adding the Processing library to my program.

Possible Causes / Solutions

As I mentioned above, a clarifying comment would be a decent compromise if assigning true to finished in the PApplet draw method cannot be avoided.

Start at the PApplet.draw method and reproduce the subclass case described in the issue, where draw invokes super.draw and event handling stops. Determine whether the intended result is a clearer warning or a behavior change, then verify the chosen outcome against the three-step reproduction.